Method for processing a substrate and substrate processing apparatus

ABSTRACT

A method for processing a substrate is provided. According to the method, a process gas is supplied to a surface of a substrate, and then a separation gas is supplied to the surface of the substrate. Moreover, a first plasma processing gas is supplied to the surface of the substrate in a first state in which a distance between the first plasma generation unit and the turntable is set at a first distance, and a second plasma processing gas is supplied to the surface of the substrate in a second state in which a distance between the second plasma generation unit and the turntable is set at a second distance shorter than the first distance. Furthermore, the separation gas is supplied to the surface of the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation application of and claims thebenefit of priority under 35 U.S.C. 120 to patent application Ser. No.14/613,656 filed on Feb. 4, 2015, which is based upon and claims thebenefit of priority of Japanese Patent Application No. 2014-23006, filedon Feb. 10, 2014, and Japanese Patent Application No. 2014-206571, filedon Oct. 7, 2014, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for processing a substrate anda substrate processing apparatus.

2. Description of the Related Art

In manufacturing semiconductor devices, a variety of film depositionprocesses is performed on a semiconductor wafer (hereinafter, “wafer”)by a film deposition method such as an ALD (Atomic Layer Deposition)method.

In recent years, so-called turntable type film deposition apparatuseshave been researched and developed as a film deposition apparatus thatperforms the ALD method. The film deposition apparatus includes arotatable turntable provided in a vacuum chamber, and the turntable hasa plurality of concave portions formed therein with a diameter slightlylarger than a wafer, on each of which a wafer is placed. The vacuumchamber includes a supply area of a reaction gas A, a supply area of areaction gas B, and separation areas separating the supply areas fromeach other all of which are provided above the turntable so as to beseparated from each other.

Moreover, the turntable type film deposition apparatus sometimesincludes a plasma generation unit mounted thereon, for example, asdisclosed in Japanese Laid-Open Patent Application Publication No.2013-161874. The film deposition process and the like of a variety of(functional) films are performed on substrates by using plasma generatedby the plasma generation unit.

However, in the film deposition process using the substrate processingapparatus as disclosed in Japanese Laid-Open Patent ApplicationPublication No. 2013-161874 and the like, what is called a loadingeffect is generated in which an amount of film deposition within asurface of a wafer varies depending on a surface area of a patternformed in the surface of the wafer.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a method for processing asubstrate and a substrate processing apparatus solving one or more ofthe problems discussed above.

More specifically, embodiments of the present invention provide a methodfor processing a substrate and a substrate processing apparatus that canprevent generation of a loading effect and can deposit a thin filmhaving a desired film quality.

According to one embodiment of the present invention, there is provideda method for processing a substrate using a substrate processingapparatus. The apparatus includes a vacuum chamber, and a turntablehaving a substrate receiving portion formed in a surface thereof toreceive a substrate thereon provided in the vacuum chamber. Theapparatus also includes a process gas supply unit configured to supply aprocess gas that adsorbs on a surface of the substrate, a first plasmaprocessing gas supply unit configured to supply a first plasmaprocessing gas to the surface of the substrate, and a second plasmaprocessing gas supply unit configured to supply a second plasmaprocessing gas to the surface of the substrate. The apparatus furtherincludes a first separation gas supply unit configured to supply aseparation gas for separating the first plasma processing gas from thefirst process gas to the surface of the substrate, and a secondseparation gas supply unit configured to supply the separation gas forseparating the second plasma processing gas from the first process gasto the surface of the substrate. The apparatus also includes a firstplasma generation unit configured to convert the first plasma processinggas to first plasma, and a second plasma generation unit configured toconvert the second plasma processing gas to second plasma. The processgas supply unit, the first separation gas supply unit, the first plasmaprocessing gas supply unit, the second plasma processing gas supply unitand the second separation gas supply unit are arranged in a rotationaldirection of the turntable in this order. In the method, the process gasis supplied to the surface of the substrate, and the separation gas issupplied to the surface of the substrate. Moreover, the first plasmaprocessing gas is supplied to the surface of the substrate in a firststate in which a distance between the first plasma generation unit andthe turntable is set at a first distance, and then the second plasmaprocessing gas is supplied to the surface of the substrate in a secondstate in which a distance between the second plasma generation unit andthe turntable is set at a second distance shorter than the firstdistance. In addition, the separation gas is supplied to the surface ofthe substrate.

According to another embodiment of the present invention, there isprovided a method for processing a substrate. In the method, asilicon-containing gas is supplied to a surface of a substrate providedin a chamber so as to cause the silicon-containing to adsorb on thesurface of the substrate. Next, a first plasma treatment is performed onthe surface of the substrate having the silicon-containing gas adsorbingon the surface of the substrate by using first plasma generated from afirst plasma processing gas containing hydrogen gas. Moreover, a secondplasma treatment is performed on the surface of the substrate subject tothe first plasma treatment by using second plasma generated from asecond plasma processing gas containing ammonia gas and no hydrogen gas.

According to another embodiment of the present invention, there isprovided a substrate processing apparatus. The apparatus includes avacuum chamber, a turntable having a substrate receiving portion formedin a surface thereof to receive a substrate thereon provided in thevacuum chamber, and a process gas supply unit configured to supply aprocess gas that adsorbs on a surface of the substrate. The apparatusalso includes a first plasma processing gas supply unit configured tosupply a first plasma processing gas to the surface of the substrate,and a second plasma processing gas supply unit configured to supply asecond plasma processing gas to the surface of the substrate. Theapparatus further includes a first separation gas supply unit configuredto supply a separation gas for separating the first plasma processinggas from the process gas to the surface of the substrate, and a secondseparation gas supply unit configured to supply the separation gas forseparating the second plasma processing gas from the process gas to thesurface of the substrate. The apparatus also includes a first plasmageneration unit configured to convert the first plasma processing gas tofirst plasma, a second plasma generation unit configured to convert thesecond plasma processing gas to second plasma, and a control unit. Theprocess gas supply unit, the first separation gas supply unit, the firstplasma processing gas supply unit, the second plasma processing gassupply unit and the second separation gas supply unit are arranged in arotational direction of the turntable in this order. The control unit isconfigured to cause the process gas supply unit to supply the processgas to the surface of the substrate, to cause the first separation gassupply unit to supply the separation gas to the surface of thesubstrate, to cause the first plasma processing gas supply unit tosupply the first plasma processing gas to the surface of the substratein a first state in which a distance between the first plasma generationunit and the turntable is set at a first distance, to cause the secondplasma processing gas supply unit to supply the second plasma processinggas to the surface of the substrate in a second state in which adistance between the second plasma generation unit and the turntable isset at a second distance shorter than the first distance, and to causethe second separation gas supply unit to supply the separation gas tothe surface of the substrate.

Additional objects and advantages of the embodiments are set forth inpart in the description which follows, and in part will become obviousfrom the description, or may be learned by practice of the invention.The objects and advantages of the invention will be realized andattained by means of the elements and combinations particularly pointedout in the appended claims. It is to be understood that both theforegoing general description and the following detailed description areexemplary and explanatory and are not restrictive of the invention asclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic vertical cross-sectional view illustrating anexample of a substrate processing apparatus according to an embodimentof the present invention;

FIG. 2 is a schematic plan view illustrating an example of the substrateprocessing apparatus according to the embodiment of the presentinvention;

FIG. 3 is a cross-sectional view cut along a concentric circle of aturntable in the plasma processing apparatus according to the embodimentof the present invention;

FIG. 4 is a vertical cross-sectional view illustrating an example of aplasma generation unit according to the embodiment of the presentinvention;

FIG. 5 is an exploded perspective view illustrating an example of theplasma generation unit according to the embodiment of the presentinvention;

FIG. 6 is a perspective view illustrating an example of a housingprovided in the plasma generation unit according to the embodiment ofthe present invention;

FIG. 7 is a plan view illustrating an example of the plasma generationunit according to the embodiment of the present invention;

FIG. 8 is a perspective view illustrating a part of a Faraday shieldprovided in the plasma generation unit according to the embodiment ofthe present invention;

FIG. 9 is a flowchart illustrating an example of a method for processinga substrate according to the embodiment of the present invention;

FIG. 10 is a schematic diagram for explaining an example of an effect ofthe method for processing the substrate according to an embodiment ofthe present invention;

FIG. 11 is a schematic diagram for explaining another example of theeffect of the method for processing the substrate according to anembodiment of the present invention;

FIGS. 12A and 12B are schematic diagrams for explaining another exampleof the effect of the method for processing the substrate according to anembodiment of the present invention;

FIG. 13 is a schematic diagram for explaining another example of theeffect of the method for processing the substrate according to anembodiment of the present invention;

FIG. 14 is a diagram illustrating an example of a process flow of themethod for processing the substrate according to an embodiment of thepresent invention;

FIGS. 15A through 15C are diagrams illustrating a chemical reactionmodel occurring on a surface of a wafer when performing the process flowillustrated in FIG. 14;

FIG. 16 is a diagram illustrating an example of a process flow of amethod for processing a substrate according to a comparative example;

FIGS. 17A through 17C are diagrams illustrating a chemical reactionmodel occurring on a surface of a wafer when performing the process flowillustrated in FIG. 16;

FIG. 18 is a chart showing a comparison result in an X line of a methodfor processing a substrate of a third working example and a method forprocessing a substrate of a comparative example when a wafer having apattern formed therein has a surface area as ten times as large a waferhaving a flat surface; and

FIG. 19 is a chart showing a comparison result in a Y line of a methodfor processing a substrate of a third working example and a method forprocessing a substrate of a comparative example when a wafer having apattern formed therein has a surface area as ten times as large a waferhaving a flat surface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description is given below of a substrate processing apparatuspreferable for implementing a method for processing a substrateaccording to embodiments of the present invention, with reference toaccompanying drawings. The substrate processing apparatus according tothe embodiments is configured to deposit a thin film by layering areaction product on a surface of a wafer W by an ALD method and toperform a plasma treatment on the wafer in the middle of depositing thethin film.

[Configuration of Substrate Processing Apparatus]

FIG. 1 is a schematic vertical cross-sectional view illustrating anexample of the substrate processing apparatus of the embodiment. FIG. 2is a schematic plan view illustrating an example of the substrateprocessing apparatus of the embodiment. Here, in FIG. 2, a depiction ofa ceiling plate 11 is omitted for the purpose of illustration.

As shown in FIG. 1, the substrate processing apparatus of the embodimentincludes a vacuum chamber 1 having an approximately circular planarshape and a turntable 2 provided in the vacuum chamber 1 and having itsrotational center in common with the center of the vacuum chamber 1 torotate a wafer W placed thereon.

The vacuum chamber 1 includes a ceiling plate (ceiling part) 11 providedin a position facing concave portions 24 of the turntable 2 describedlater and a chamber body 12. Moreover, a seal member 13 having aring-like shape is provided in a periphery in an upper surface of thechamber body 12. The ceiling plate 11 is configured to be detachable andattachable from and to the chamber body 12. A diameter dimension (innerdiameter dimension) of the vacuum chamber 1 when seen in a plan view isnot limited, but can be, for example, set at about 1100 mm.

A separation gas supply pipe 51 is connected to a central part in anupper surface of the ceiling plate 11 and is further communicated with acentral part of an upper surface side in the vacuum chamber 1 through ahole to supply a separation gas for preventing different process gasesfrom mixing with each other in a central area C.

The turntable 2 is fixed to a core portion 21 having an approximatelycylindrical shape at the central part, and is configured to be rotatableby a drive unit 23 in a clockwise fashion as illustrated in FIG. 2 as anexample, around a rotational shaft 22 connected to a lower surface ofthe core portion 21 and extending in a vertical direction, which forms avertical axis. The diameter dimension of the turntable 2 is not limited,but can be set at, for example, about 1000 mm.

The rotational shaft 22 and the drive unit 23 are accommodated in acasing body 20, and a flange portion at an upper surface side of thecasing body 20 is hermetically attached to a lower surface of a bottomportion of the vacuum chamber 1. A purge gas supply pipe 72 forsupplying nitrogen gas or the like as a purge gas (separation gas) to anarea below the turntable 2.

A peripheral side of the core portion 21 in a bottom part 14 of thevacuum chamber 1 forms a protruding part 12 a by being formed into aring-like shape so as to come to close to the lower surface of theturntable 2.

As shown in FIG. 2, circular concave portions 24 are formed in a surfaceof the turntable 2 as a substrate receiving area to receive wafers Whaving a diameter dimension of, for example, 300 mm thereon. The concaveportions 24 are provided at a plurality of locations, for example, atfive locations along a rotational direction of the turntable 2. Each ofthe concave portions 24 has an inner diameter slightly larger than thediameter of the wafer W, more specifically, larger than the diameter ofthe wafer W by about 1 to 4 mm. Furthermore, the depth of each of theconcave portions 24 is configured to be approximately equal to orgreater than the thickness of the wafer W. Accordingly, when the wafer Wis accommodated in the concave portion 24, the surface of the wafer W isas high as, or lower than a surface of the turntable 2 where the wafer Wis not placed. Here, even when the depth of each of the concave portions24 is greater than the thickness of the wafer W, the depth of each ofthe concave portion 24 is preferred to be equal to or smaller than aboutthree times the thickness of the wafer W because too deep concaveportions 24 may affect the film deposition.

Through holes not illustrated in the drawings are formed in a bottomsurface of the concave portion 24 to allow, for example, three liftingpins described later to push up the wafer W from below and to lift thewafer W.

As illustrated in FIG. 2, for example, five nozzles 31, 32, 34, 41 and42 each made of, for example, quartz are arranged in a radial fashion atintervals in the circumferential direction of the vacuum chamber 1 atrespective positions opposite to a passing area of the concave portions24. Each of the nozzles 31, 32, 34, 41 and 42 is arranged between theturntable 2 and the ceiling plate 11. These nozzles 31, 32, 34, 41 and42 are each installed, for example, so as to horizontally extend facingthe wafer W from an outer peripheral wall of the vacuum chamber 1 towardthe central area C.

In the example illustrated in FIG. 2, a first process gas nozzle 31, aseparation gas nozzle 42, a first plasma processing gas nozzle 32, asecond plasma processing gas nozzle 34, a second plasma processing gasnozzle 34 and a separation gas nozzle 41 are arranged in a clockwisefashion (in the rotational direction of the turntable 2) in this order.However, the substrate processing apparatus of the embodiments is notlimited to this form, and the turntable 2 may rotate in acounterclockwise fashion. In this case, the first process gas nozzle 31,the separation gas nozzle 42, the first plasma processing gas nozzle 32,the second plasma processing gas nozzle 34 and the separation gas nozzle41 are arranged in this order in the counterclockwise fashion.

As illustrated in FIG. 2, plasma generation units 81 a and 81 b areprovided above the first plasma processing gas nozzle 32 and the secondplasma processing gas nozzle 34, respectively, to convert plasmaprocessing gases discharged from the respective plasma processing gasnozzles 32 and 34. A description is given later of the plasma generationunits 81 a and 81 b.

Here, in the embodiment, although an example of arranging a singlenozzle in each process area is illustrated, a configuration of providinga plurality of nozzles in each process area is also possible. Forexample, the first plasma processing gas nozzle 32 may be constituted ofa plurality of plasma processing gas nozzles, each of which isconfigured to supply argon (Ar) gas, ammonia (NH₃) gas, hydrogen (H₂)gas or the like, or may be constituted of only a single plasmaprocessing gas nozzle configured to supply a mixed gas of argon gas,ammonia gas and hydrogen gas.

The first process gas nozzle 31 forms a first process gas supply part.Moreover, the first plasma processing gas nozzle 32 forms a first plasmaprocessing gas supply part, and the second plasma processing gas nozzle34 forms a second plasma processing gas supply part. Furthermore, eachof the separation gas nozzles 41 and 42 forms a separation gas supplypart.

Each of the nozzles 31, 32, 34, 41 and 42 is connected to each gassupply source not illustrated in the drawings through a flow regulatingvalve.

A silicon-containing gas may be used as an example of the first processgas supplied from the first process gas nozzle 31 such as DCS[dichlorosilane], HCD [hexachlorodisilane], DIPAS[diisopropylamino-silane], 3DMAS [tris(dimethylamino)silane] gas, BTBAS[bis(tertiary-butyl-amino)silane] or the like. Also, a metal-containinggas may be used as an example of the first process gas supplied from thefirst process gas nozzle 31 such as TiCl₄ [titanium tetrachloride], Ti(MPD) (THD)₂ [titanium methylpentanedionato,bis(tetramethylheptanedionato)], TMA [trimethylaluminium], TEMAZ[Tetrakis(ethylmethylamino)zirconium], TEMHF [tetrakis(ethylmethylamino)hafnium], Sr(THD)₂ [strontiumbis(tetramethylheptanedionato)] or the like.

The plasma processing gases supplied from the first plasma processinggas nozzle 32 and the second plasma processing gas nozzle 34 can beproperly selected depending on intended purpose of the plasma. Forexample, argon gas or helium (He) gas mainly used for plasma generation,and a mixed gas of ammonia gas and hydrogen gas for nitrizing the firstprocess gas adsorbing on the wafer W and modifying the obtained nitrizedfilm are cited as examples. Here, the plasma processing gases dischargedfrom the first plasma processing gas nozzle 32 and the second plasmaprocessing gas nozzle 34 may be the same gas species, or may bedifferent gas species from each other. Each of the plasma processinggases can be selected depending on a desired plasma treatment.

For example, nitrogen (N₂) gas or the like is cited as an example of theseparation gas supplied from the separation gas nozzles 41 and 42.

As discussed above, in the example illustrated in FIG. 2, the firstprocess gas nozzle 31, the separation gas nozzle 42, the first plasmaprocessing gas nozzle 32, the second plasma processing gas nozzle 34 andthe separation gas nozzle 41 are arranged in this order in a clockwisefashion (in the rotational direction of the turntable 2). In otherwords, in an actual process of the wafer W, the wafer W to which thefirst process gas has been supplied from the first process gas nozzle 31is sequentially exposed to the separation gas from the separation gasnozzle 42, the plasma processing gas from the first plasma processinggas nozzle 32, the plasma processing gas from the second plasmaprocessing gas nozzle 34, and the separation gas from the separation gasnozzle 41 in this order.

Gas discharge holes 33 for discharging each of the above-mentioned gasesare formed in each lower surface (the surface facing the turntable 2) ofthe gas nozzles 31, 32, 34, 41 and 42 along a radial direction of theturntable 2 at a plurality of locations, for example, at regularintervals. Each of the nozzles 31, 32, 34, 41 and 42 is arranged so thata distance between a lower end surface of each of the nozzles 31, 32,34, 41 and 42 and an upper surface of the turntable 2 is set at, forexample, about 1 to 5 mm.

An area under the first process gas nozzle 31 is a first process area P1to allow the first process gas to adsorb on the wafer W. An area underthe first plasma processing gas nozzle 32 is a second process area P2 totreat a thin film on the wafer W by first plasma, and an area under thesecond plasma processing gas nozzle 34 is a third process area P3 totreat the thin film on the wafer W by second plasma.

FIG. 3 illustrates a cross-sectional view cut along a concentric circleof the turntable 2 of the film deposition apparatus of the embodiment.Here, FIG. 3 illustrates the cross-sectional view from one of theseparation area D to the other separation area D by way of the firstprocess area P1.

As shown in FIG. 3, approximately sectorial convex portions 4 areprovided on the ceiling plate 11 of the vacuum chamber 1 in theseparation areas D. Flat low ceiling surfaces 44 (first ceilingsurfaces) that are lower surfaces of the convex portions 4 and ceilingsurfaces 45 (second ceiling surfaces) that are higher than the ceilingsurfaces 44 provided on both sides of the ceiling surfaces 44 in acircumferential direction, are formed in the vacuum chamber 1.

As illustrated in FIG. 2, the convex portions 4 forming the ceilingsurfaces 44 have a sectorial planar shape whose apexes are cut into anarc-like shape. Moreover, each of the convex portions 4 has a grooveportion 43 formed so as to extend in the radial direction in the centerin the circumferential direction, and each of the separation gas nozzles41 and 42 is accommodated in the groove portion 43. Here, a periphery ofeach of the convex portions 4 (a location on the peripheral side of thevacuum chamber 1) is bent into a L-shaped form so as to face an outerend surface of the turntable 2 and to be located slightly apart from thechamber body 12 in order to prevent each of the process gas from mixingwith each other.

As illustrated in FIG. 3, a nozzle cover 230 is provided on the upperside of the first process gas nozzle 31 in order to cause the firstprocess gas to flow along the wafer W and so as to cause the separationgas to flow through a location close to the ceiling plate 11 of thevacuum chamber 1 while flowing away from the neighborhood of the waferW. As illustrated in FIG. 3, the nozzle cover 230 includes anapproximately box-shaped cover body 231 whose lower surface side is opento accommodate the first process gas nozzle 31 and current plates 232having a plate-like shape and connected to the lower open ends of thecover body 231 on both upstream and downstream sides in the rotationaldirection of the turntable 2. Here, a side wall surface of the coverbody 231 on the rotational center side of the turntable 2 extends towardthe turntable 2 (i.e., downward) so as to face a tip of the firstprocess gas nozzle 31. In addition, the side wall surface of the coverbody 231 on the peripheral side of the turntable 2 is cut off so as notto interfere with the first process gas nozzle 31.

Next, a detailed description is given below of the first plasmageneration unit 81 a and the second plasma generation unit 81 b providedabove the first and second plasma processing gas nozzles 32 and 34,respectively. Here, in the embodiment, although each of the first plasmageneration unit 81 a and the second plasma generation unit 81 b canperform an independent plasma treatment, each specific configuration canbe similar to each other.

FIG. 4 illustrates a vertical cross-sectional view of an example of theplasma generation units 81 a and 81 b of the embodiment. Also, FIG. 5illustrates an exploded perspective view of an example of the plasmageneration units 81 a and 81 b of the embodiment. Furthermore, FIG. 6illustrates a perspective view of an example of a housing provided inthe plasma generation units 81 a and 81 b of the embodiment.

The plasma generation units 81 a and 81 b are configured to wind anantenna 83 constituted of a metal wire or the like, for example, triplyaround the vertical axis. Moreover, as illustrated in FIG. 2, each ofthe plasma generation unit 81 a and 81 b is arranged so as to surround aband area extending in the radial direction of the turntable 2 when seenin a plan view and to cross the diameter of the wafer W on the turntable2.

The antenna 83 is, for example, connected to a high frequency powersource 85 having a frequency of 13.56 MHz and an output power of 5000 Wby way of a matching box 84. Then, the antenna 83 is provided to behermetically separated from an inner area of the vacuum chamber 1. Here,a connection electrode 86 is provided to electrically connect theantenna 83 with the matching box 84 and the high frequency power source85.

As illustrated in FIGS. 4 and 5, an opening 11 a having an approximatelysectorial shape when seen in a plan view is formed in the ceiling plate11 above the first plasma processing gas nozzle 32.

As illustrated in FIG. 4, an annular member 82 is hermetically providedin the opening 11 a along the verge of the opening 11 a. The housing 90described later is hermetically provided on the inner surface side ofthe annular member 82. In other words, the annular member 82 ishermetically provided at a position where the outer peripheral side ofthe annular member 82 faces the inner surface 11 b of the opening 11 ain the ceiling plate 11 and the inner peripheral side of the annularmember 82 faces a flange part 90 a of the housing 90 described later.The housing 90 made of, for example, a derivative of quartz is providedin the opening 11 a through the annular member 82 in order to arrangethe antenna 83 at a position lower than the ceiling plate 11.

Moreover, as illustrated in FIG. 4, the annular member 82 includes abellows 82 a expandable in the vertical direction. Furthermore, theplasma generation units 81 a and 81 b are formed to be able to move upand down independently of each other by a drive mechanism (elevatingmechanism) not illustrated in the drawings such as an electric actuatoror the like. By causing the bellows 82 a to extend and contract inresponse to the rise and fall of the plasma generation units 81 a and 81b, each distance between each of the plasma generation units 81 a and 81b and the wafer W (i.e., turntable 2) (which may be called a distance ofa plasma generation space) during the plasma treatment can be changed.

As illustrated in FIG. 6, the casing 90 is configured to have aperipheral part horizontally extending along the circumferentialdirection on the upper side so as to form the flange part 90 a and acentral part getting recessed inward toward the inner area of the vacuumchamber 1 when seen in a plan view.

The housing 90 is arranged to cross the diameter of the wafer W in theradial direction of the turntable 2 when the wafer W is located underthe housing 90. Here, as illustrated in FIG. 4, a seal member 11 c suchas an O-ring or the like is provided between the annular member 82 andthe ceiling plate 11.

An internal atmosphere of the vacuum chamber 1 is sealed by the annularmember 82 and the housing 90. More specifically, the annular member 82and the housing 90 are set in the opening 11 a, and then the housing 90is pressed downward through the whole circumference by a pressing member91 formed into a frame-like shape along the contact portion of theannular member 82 and the housing 90. Furthermore, the pressing member91 is fixed to the ceiling plate 11 by volts and the like notillustrated in the drawings. This causes the internal atmosphere of thevacuum chamber 1 to be sealed. Here, in FIG. 5, a depiction of theannular member 82 is omitted for simplification.

As illustrated in FIG. 6, a projection portion 92 vertically extendingtoward the turntable 2 is formed in a lower surface of the housing 90 soas to surround each of the process areas P2 and P3 under the housing 90along each circumferential direction thereof. Then, the first plasmaprocessing gas nozzle 32 and the second plasma processing gas nozzle 34are accommodated in an area surrounded by an inner circumferentialsurface of the projection portion 92, the lower surface of the housing90 and the upper surface of the turntable 2. Here, the projectionportion 92 at the base end portion (the inner wall side of the vacuumchamber 1) of each of the first plasma processing gas nozzle 32 and thesecond plasma processing gas nozzle 34 is cut off so as to be formedinto an approximately arc-like form along each of the first plasmaprocessing gas nozzle 32 and the second plasma processing gas nozzle 34.

As illustrated in FIG. 4, the projection portion 92 is formed on thelower side of the housing 90 along the circumferential directionthereof. The seal member 11 c is not exposed to the plasma due to theprojection portion 92, and that is to say, is separated from the plasmageneration space. Because of this, even if the plasma is likely todiffuse, for example, to the seal member 11 c side, because the plasmagoes toward the seal member 11 c byway of the lower side of theprojection portion 92, the plasma becomes inactivated before reachingthe seal member 11 c.

A grounded Faraday shield 95 that is formed so as to approximately fitalong an inner shape of the housing 90 and is made of a conductiveplate-like body, for example, a metal plate such as a copper plate andthe like, is installed in the housing 90. The Faraday shield 95 includesa horizontal surface 95 a horizontally formed so as to be along thebottom surface of the housing 90 and a vertical surface 95 b extendingupward from the outer edge of the horizontal surface 95 a through thewhole circumference, and may be configured to be approximately hexagonwhen seen in a plan view.

FIG. 7 illustrates a plan view of an example of the plasma generationunit according to the embodiment, and FIG. 8 illustrates a perspectiveview of a part of the Faraday shield provided in the plasma generationunit according to the embodiment.

Upper end edges of the Faraday shield 95 on the right side and the leftside extend rightward and leftward, respectively, when seen from therotational center of the turntable 2 horizontally, and form supports 96.As illustrated in FIG. 5, a frame body 99 is provided between theFaraday shield 95 and the housing 90 to support the support 96 frombelow and so as to be supported by the flange part 90 a of the housing90 on the central area C and the outer periphery of the turntable 2.

When an electric field generated by the antenna 83 reaches the wafer W,a pattern (electrical wiring and the like) formed inside the wafer W maybe damaged. Because of this, as illustrated in FIG. 8, many slits 97 areformed in the horizontal surface 95 a in order to prevent an electricfield component of the electric field and a magnetic field (i.e., anelectromagnetic field) generated by the antenna 83 from going toward thewafer W located below and to allow the magnetic field to reach the waferW.

As illustrated in FIGS. 7 and 8, the slits 97 are formed under theantenna 83 along the circumferential direction so as to extend in adirection perpendicular to a winding direction of the antenna 83. Here,the slits 97 are formed to have a width dimension equal to or less thanabout 1/10000 of a wavelength of the high frequency power supplied tothe antenna 83. Moreover, electrically conducting paths 97 a made of agrounded electric conductor and the like are arranged on one end and theother end in a lengthwise direction of each of the slits 97 a so as tostop open ends of the slits 97 a. An opening 98 is formed in an area outof the area where the slits 97 are formed in the Faraday shield 95, thatis to say, at the central side of the area where the antenna 83 is woundaround to be able to observe a light emitting state of the plasmatherethrough. Here, in FIG. 2, the slits 97 are omitted for simplicity,and an example of the slit formation area is expressed by alternate longand short dash lines.

As illustrated in FIG. 5, an insulating plate 94 made of quartz and thelike having a thickness dimension of, for example, about 2 mm, isstacked on the horizontal surface 95 a of each of the Faraday shields 95in order to ensure insulation properties from the plasma generationunits 81 a and 81 b placed on each of the Faraday shields 95. In otherwords, each of the plasma generation units 81 a and 81 b is arranged soas to face the inside of the vacuum chamber 1 (the wafer W on theturntable 2) through the housing 90, the Faraday shield 95 and theinsulating plate 94.

A description is given below of other components of the substrateprocessing apparatus of the embodiment again.

As illustrated in FIG. 2, a side ring 100 that forms a cover body isarranged at a position slightly lower than the turntable 2 and outeredge side of the turntable 2. Exhaust openings 61 and 62 are formed inan upper surface of the side ring 100 at two locations apart from eachother in the circumferential direction. In other words, two exhaustports are formed in a bottom surface of the vacuum chamber 1, and theexhaust openings 61 and 62 are formed at locations corresponding to theexhaust ports in the side ring 100.

In the present specification, one of the exhaust openings 61 and 62 iscalled a first opening 61 and the other of the exhaust openings 61 and62 is called a second opening 62. Here, the first exhaust opening 61 isformed between the separation gas nozzle 42 and the first plasmageneration unit 81 a located on the downstream side of the separationgas nozzle 42 in the rotational direction of the turntable 2.Furthermore, the second exhaust opening 62 is formed between the secondplasma generation unit 81 b and the separation area D on the downstreamside of the plasma generation unit 81 b in the rotational direction ofthe turntable 2.

The first exhaust opening 61 is to evacuate the first process gas andthe separation gas, and the second exhaust opening 62 is to evacuate theplasma processing gas and the separation gas. Each of the first exhaustopening 61 and the second exhaust opening 62 is, as shown in FIG. 1,connected to an evacuation mechanism such as a vacuum pump 64 through anevacuation pipe 63 including a pressure controller 65 such as abutterfly valve.

As described above, because the housings 90 are arranged from thecentral area C side to the outer peripheral side, a gas flowing from theupstream side in the rotational direction of the turntable 2 to theplasma treatment area P2 and P3 may be blocked from going to theevacuation opening 62 by the housings 90. In response to this, agroove-like gas flow passage 101 (see FIGS. 1 and 2) is formed in theupper surface of the side ring 100 on the outer edge side of the housing90 to allow the gas to flow therethrough.

As shown in FIG. 1, in the center portion on the lower surface of theceiling plate 11, a protrusion portion 5 is provided that is formed intoan approximately ring-like shape along the circumferential directioncontinuing from the central area C side of the convex portion 4 so as tohave a lower surface formed as high as the lower surface of the convexportion 4 (ceiling surface 44). A labyrinth structure 110 is providedcloser to the rotational center side of the turntable 2 than theprotrusion portion 5 and above the core portion 21 to suppress thevarious gases from mixing with each other in the center area C.

As discussed above, because the housings 90 are formed at the locationclose to the central area C, the core portion 21 supporting the centralportion of the turntable 2 is formed at the rotational center side sothat a location above the turntable 2 avoids the housing 90. Due tothis, the various gases are more likely to mix with each other at thecentral area C side than at the outer peripheral side. Hence, by formingthe labyrinth structure 110 above the core portion 21, a flow path canbe made longer to be able to prevent the gases from mixing with eachother.

More specifically, the labyrinth structure 110 has a wall partvertically extending from the turntable 2 toward the ceiling plate 11and a wall part vertically extending from the ceiling plate 11 towardthe turntable 2 that are formed along the circumferential direction,respectively, and are arranged alternately in the radial direction ofthe turntable 2. In the labyrinth structure 110, for example, a firstprocess gas discharged from the first process gas nozzle 31 and headingfor the central area C needs to go through the labyrinth structure 110.Due to this, the first process gas decreases in speed with thedecreasing the distance from the central area C and becomes unlikely todiffuse. As a result, the first process gas is pushed back by theseparation gas supplied to the central area C before reaching thecentral area C. Moreover, other gases likely to head for the centralarea C are difficult to reach the central area C by the labyrinthstructure 110 in a similar way. This prevents the process gases frommixing with each other in the central area C.

On the other hand, the separation gas supplied from the separation gassupply pipe 51 is likely to diffuse swiftly in the circumferentialdirection at first, but decreases in speed as going through thelabyrinth structure 110. In this case, nitrogen gas is likely to intrudeinto a very narrow area such as a gap between the turntable 2 and theprojection portion 92, but flows to a relatively large area such as anarea where the transfer arm 10 moves in and out of the vacuum chamber 1because the labyrinth structure 110 decreases the flowing speed thereof.Because of this, nitrogen gas is prevented from flowing into a spaceunder the housing 90.

As illustrated in FIG. 1, a heater unit 7 that is a heating mechanism isprovided in a space between the turntable 2 and the bottom part 14 ofthe vacuum chamber 1. The heater unit 7 is configured to be able to heatthe wafer W on the turntable 2 through the turntable 2 up to, forexample, a range from room temperature to about 760 degrees C.Furthermore, as illustrated in FIG. 1, a side cover member 71 a isprovided on a lateral side of the heater unit 7, and an upper coveringmember 7 a is provided so as to cover the heater unit 7 from above. Inaddition, purge gas supply pipes 73 for purging a space in which theheater unit 7 is provided are provided in the bottom part 14 of thevacuum chamber 1 under the heater unit 7 at multiple locations along thecircumferential direction.

As illustrated in FIG. 2, a transfer opening 15 is provided in the sidewall of the vacuum chamber 1 to transfer the wafer W between a transferarm 10 and the turntable 2. The transfer opening 15 is configured to behermetically openable and closable by a gate valve G. Moreover, a cameraunit 10 a is provided above the ceiling plate 11 in the area where thetransfer arm moves in and out of the vacuum chamber 10 a in order todetect a peripheral part of the wafer W. The camera unit 10 a is used todetect, for example, presence or absence of the wafer W on the transferarm 10, a positional shift of the wafer W placed on the turntable 2 anda positional shift of the wafer W on the transfer arm 10. The cameraunit 10 a is configured to have a field of view wide enough to cover adiameter dimension of the wafer W.

The wafer W is transferred between the concave portion 24 of theturntable 2 and the transfer arm 10 at a position where the concaveportion 24 of the turntable 2 faces the transfer opening 15.Accordingly, lift pins and an elevating mechanism that are notillustrated in the drawings are provided at a position under theturntable 2 corresponding to the transferring position to lift the waferW from the back surface by penetrating through the concave portion 24.

Moreover, as illustrated in FIG. 1, a control unit 120 constituted of acomputer to control operation of the whole apparatus is provided in thesubstrate processing apparatus of the embodiment. A program to implementthe substrate process described later is stored in a memory of thecontrol unit 120. This memory stores the program to perform thesubstrate process described later. This program is constituted ofinstructions of step groups to cause the apparatus to implementoperations described later, and is installed into the control unit 120from a memory unit 121 that is a storage medium such as a hard disk, acompact disc, a magnetic optical disk, a memory card and a flexibledisk.

[Method for Processing a Substrate]

Next, a description is given below of a method for processing asubstrate using the substrate processing apparatus according to anembodiment of the present invention.

In the ALD method using a turntable type substrate processing apparatusutilizing plasma, in general, film deposition of a predetermined filmand the film quality enhancement thereof are performed at a relativelylow temperature by utilizing the energy of radicals and ions generatedby the plasma after causing a predetermined process gas to adsorb on awafer W. However, when depositing a nitride film such as a siliconnitride film on a wafer W, although the adsorption of the process gas onthe wafer W is readily performed on a relatively short time, nitridingthe adsorbed process gas needs a large amount of nitriding gas and along reaction time. In the turntable type substrate processingapparatus, because there are limitations of a number of plasmageneration units capable of being installed and a range of plasmatreatment area (which depends on the electrode size and the likethereof) due to the apparatus size and the apparatus cost, a desiredfilm quality needs to be acquired by the limited number of plasmageneration units and the limited plasma treatment area with desiredproductivity.

Moreover, in the film deposition process, a phenomenon is caused that afilm deposition rate varies depending on a surface area of an electricalwiring pattern preliminarily formed in the wafer W (i.e., loadingeffect). In particular, in order to respond to a demand ofminiaturization of the electrical wiring pattern of semiconductordevices in recent years, a substrate processing apparatus is needed thatcan prevent the generation of the loading effect and can form a thinfilm having a desired film quality. It is known that the loading effectin a reaction system for forming a nitride film is likely to occur whena pressure of the nitriding part is high and is unlikely to occur as thepressure of the nitriding part becomes low. However, in the turntabletype substrate processing apparatus, when the pressure of the nitridingpart is reduced, a pressure of an adsorption part where the adsorptionof a process gas occurs decreases at the same time, which decreases anadsorption efficiency of the process gas and the productivity, andincreases the productive cost. Furthermore, because increasing thevacuum pump in size, installing a high vacuum pump and the like areneeded, the apparatus cost increases.

Therefore, the substrate processing method according to the embodimentis implemented by using a substrate processing apparatus including:

a vacuum chamber;

a turntable having a substrate receiving portion to receive a substrateon a surface thereof provided in the vacuum chamber;

a first process gas supply unit configured to supply a first process gasthat adsorbs to a surface of the substrate;

a first plasma processing gas supply unit and a second plasma processinggas supply unit configured to supply a first plasma processing gas and asecond plasma processing gas to the surface of the substrate,respectively;

a first separation gas supply unit configured to supply a separation gasto separate the first plasma processing gas from the first process gasand;

a second separation gas supply unit configured to supply the separationgas to separate the second plasma processing gas from the first processgas; and

a first plasma generation unit and a second plasma generation unitconfigured to convert the first plasma processing gas and the secondplasma processing gas to first plasma and second plasma, respectively,

wherein the first process gas supply unit, the first separation gassupply unit, the first plasma processing gas supply unit, the secondplasma processing gas supply unit and the second separation gas supplyunit are arranged in this order in a rotational direction of theturntable.

More specifically, a method for processing a substrate of theembodiments includes steps of:

supplying the first process gas to the substrate (S100);

supplying the separation gas to the substrate to which the first processgas was supplied (S110);

supplying the first plasma processing gas to the substrate to which theseparation gas was supplied in a first state in which a distance betweenthe first plasma generation unit and the turntable is a first distance(S120);

supplying the second plasma processing gas to the substrate to which thefirst plasma processing gas was supplied in a second state in which adistance between the second plasma generation unit and the turntable isa second distance shorter than the first distance (S130); and

supplying the separation gas to the substrate to which the second plasmaprocessing gas was supplied.

The method for processing the substrate according to the embodimentscauses the substrate to pass a first plasma treatment area in which thedistance between the first plasma generation unit and the turntable isthe first distance, and subsequently to pass a second plasma treatmentarea in which the distance between the second plasma generation unit andthe turntable is the second distance shorter than the first distance. Inother words, the substrate is caused to pass an area in which ion energyis low and a radical concentration is low (second process area P2) andthen to pass an area in which the ion energy is high and the radicalconcentration is high (third process area P3). This enables thegeneration of the loading effect to be prevented, and makes it possibleto form a thin film having a desired film quality.

A detailed description is given below of each of the steps starting fromthe carry-in of the wafers W by citing specified embodiments.

To begin with, in carrying wafers W in the vacuum chamber 1, the gatevalve G is opened. Then, the wafers W are placed on the turntable 2 bythe transfer arm 10 through the transfer opening 15 while rotating theturntable 2 intermittently.

Next, the gate valve G is closed and the wafers W are heated to apredetermined temperature by the heater unit 7. Subsequently, the firstprocess gas is discharged from the first process gas nozzle 31 at apredetermined flow rate, and plasma processing gases are supplied fromthe first plasma processing gas nozzle 32 and the second plasmaprocessing gas nozzle 34 at predetermined flow rates, respectively.

Next, a distance between the first plasma generation unit 81 a and theturntable 2 is set at a predetermined first distance. Then, a distancebetween the second plasma generation unit 81 b and the turntable 2 isset at a second distance shorter than the first distance.

The inside of the vacuum chamber 1 is adjusted to a predeterminedpressure by the pressure controller 65. The plasma generation units 81 aand 81 b supply high frequency power of predetermined outputs toantennas 83 thereof, respectively.

The first process gas adsorbs on each surface of the wafers W in thefirst process area P1 by the rotation of the turntable 2 (S100). Thewafers W on which the first process gas adsorbs pass the separation areaD by the rotation of the turntable 2 (S110). In the separation area D,the separation gas is supplied to each of the surfaces of the wafers W,and unnecessary physically absorbed materials with respect to the firstprocess gas are removed.

The wafers W subsequently pass the second process area P2 by therotation of the turntable 2 (S120). In the second process area P2, thefirst process gas is nitrided by plasma of the plasma processing gassupplied from the first plasma processing gas nozzle 32, and the formednitride film is treated to modify the quality thereof.

In general, ions and radicals are known as active species (precursors)generated by plasma converted from a plasma processing gas. The ionsmainly contribute to a modification treatment of a nitride film, and theradicals mainly contribute to a deposition process of a nitride film.Moreover, it is known that the ions have shorter life than the radicalsand that the ion energy reaching the wafers W widely decreases by makingthe distances between the plasma generation units 81 a and 81 b and theturntable 2 longer.

Here, in the second process area P2, the distance between the firstplasma generation unit 81 a and the turntable 2 is set at the firstdistance longer than the second distance described later (see S120). Inthe second process area P2, the ions reaching the wafers W widelydecrease due to the relatively long first distance, and the radicals aremainly supplied to the wafers W. In other words, in the second processarea P2, the first process gas on the wafers W is nitrided (initialized)by the first plasma having a relatively low ion energy, and one or moremolecular layers of the nitride film that are a component of the thinfilm are deposited. Furthermore, the deposited nitride film is treatedby the second plasma to modify the quality thereof.

In addition, in the initial stage of the film deposition process, whenplasma whose precursor has a significant influence on the wafers W isused such as plasma having great ion energy, the wafers W may benitrided in themselves. In terms of this, in the process performed inthe second process area P2, to begin with, the plasma treatment usingplasma having low ion energy is preferred to be performed.

The first distance is not limited, but is preferred to be set in a rangefrom 45 to 120 mm in terms of efficiently depositing the nitride film onthe wafers W by using the plasma having relatively low ion energy.

Next, the wafers W having passed the second process area P2 pass thethird process area P3 by the rotation of the turntable 2 (S130). In thethird process area P3, the first process gas is nitrided by the plasmaof the plasma processing gas supplied from the second plasma processinggas nozzle 34 as well as the second process area P2, thereby treatingthe deposited nitride film for modification treatment.

Here, in the third process area P3, the distance between the secondplasma generation unit 81 b and the turntable 2 is set at the seconddistance smaller than the above-mentioned first distance (see S130). Dueto the second distance relatively smaller than the first distance, inthe third process area P3, an amount of the ions reaching the wafers Wis more than that in the second process area P2. Here, it should benoted that an amount of radicals in the third process area P3 is alsomore than that in the second process area P2. Accordingly, in the thirdprocess area P3, the first process gas on the wafers W is nitride byplasma having relatively high ion energy and high-dense radicals, andthe deposited nitride film is more efficiently modified than that in thesecond process area P2.

The second distance is not limited as long as the second distance isshorter than the first distance, but is preferred to be set in a rangefrom 20 to 60 mm in terms of more efficiently modifying the nitridefilm.

The wafers W treated by the second plasma pass the separation area D bythe rotation of the turntable 2 (S140). The separation area D is an areato separate the first process area P1 from the third process area P3 sothat the unnecessary nitriding gas and the modifying gas do not intrudeinto the first process area P1.

In the embodiments, by keeping the turntable 2 rotating, the adsorptionof the first process gas on the wafers W, the nitriding process of thefirst process gas adsorbing on the wafers W, and the plasma modificationof the reaction product are performed in this order many times. In otherwords, the film deposition process by the ALD method and themodification process of the deposited film are performed many times byrotating the turntable 2.

Here, in the substrate processing apparatus of the embodiments, theseparation areas D are arranged between the process areas P1 and P2 onboth sides in the circumferential direction of the turntable 2. Becauseof this, in the separation areas D, each of the process gas and theplasma processing gases flows toward each of the exhaust openings 61 and62 while being prevented from mixing with each other.

Next, a description is given below of an example of preferredimplementing conditions when performing the method, for example, thefilm deposition of the nitride film on the wafers W and the modificationtreatment of the deposited nitride film.

A flow rate of the first process gas in the film deposition process isnot limited, but can be set at, for example, a range of about 900 to1500 sccm.

A flow rate of an ammonia-containing gas contained in the plasmaprocessing gases is not limited, but can be set at, for example, a rangeof about 4000 to 5000 sccm.

The pressure inside the vacuum chamber 1 is not limited, but can be setat, for example, a range of about 0.75 to 0.9 Torr.

The temperature of the wafers W is not limited, but can be set at, forexample, a range of about 350 to 450 degrees C.

The rotational speed of the turntable 2 is not limited, but can be setat, for example, a range of 60 to 300 rpm.

Next, a more detailed description is given below of the embodiments ofthe present invention by citing specific working examples.

Working Example 1

In the plasma treatment of the method for processing the substrate ofthe embodiments, a description is given below of a working example ofhaving acknowledged that the generation of the loading effect can beprevented and a thin film having a desired film quality can be depositedby passing a wafer through an area having low ion energy and a lowradical concentration (the second process area P2) and then passing thewafer through an area having high ion energy and a high radicalconcentration (the third process area P3).

A film deposition process was performed on a wafer W under the followingconditions by the method for processing the substrate as described withreference to FIG. 9 by using the substrate processing apparatus of theembodiments as described with reference to FIGS. 1 through 8.

The film deposition process of the working example 1 was as follows:

First process gas: DCS (dichlorosilane)

Processing gas in step S120: NH₃=4000 sccm

First distance in step S120: 90 mm

Processing gas in step S130: NH₃/Ar/H₂=300/1900/600 sccm

Second distance in step S130: 37.5 mm.

Moreover, as a comparative example 1, the film deposition process of thecomparative example 1 was performed as well as the method of the workingexample 1 except that the second distance in step S130 was set at 90 mm.

Furthermore, as a comparative example 2, the film deposition process ofthe comparative example 1 was performed as well as the method of theworking example 1 except that the first distance in step S120 was set at37.5 mm and that the second distance in step S130 was set at 90 mm.

By measuring each film thickness of reaction products (nitride films) onthe wafers W obtained after performing the working example 1 and thecomparative examples 1 and 2, a film deposition rate per one cycle fromsteps S100 to S140 and uniformity within a surface of the wafer W of thedeposited film were obtained.

FIG. 10 shows a schematic chart for explaining an example of an effectof the method for processing the substrate of the working example 1.More specifically, bar graphs in FIG. 10 show results regarding a filmdeposition rate, and a line graph shows results of the uniformity withinthe surface of the wafer W. Here, data of the uniformity within thesurface of the wafer W are values obtained by dividing a remainder ofsubtracting a minimum film thickness from a maximum film thicknesswithin the wafer surface by the maximum film thickness, and indicate asuperior uniformity within the surface of the wafer W as the valuesdecrease.

As clearly noted from the film deposition rates shown in FIG. 10, thereis not much difference in film deposition rate per one cycle among theworking example 1 and the comparative examples 1 and 2. Because the filmdeposition rate was almost the same as the other examples even in thecomparative example 1 in which the first and second distances are both90 mm, the adsorbed first process gas was considered to be preferablynitrided in all of the examples.

On the other hand, from the results of the uniformity within the surfaceof the wafer W shown in FIG. 10, it is noted that the method forprocessing the substrate of the working example 1 can deposit a filmhaving the uniformity more excellent than those of the method forprocessing the substrate of the comparative examples 1 and 2.

From the results discussed above, it is noted that the method forprocessing the substrate according to the working example 1 can deposita film having very excellent uniformity within a surface of a wafer Wwhile maintaining a certain film deposition rate by passing thesubstrates through an area having small ion energy and a low radicalconcentration (second process area P2) and then passing the substratesthrough an area having great ion energy and a high radical concentration(third process area P3) in a plasma treatment.

In addition, a wet etching was performed in the obtained film by usingdilute hydrofluoric acid of 0.5%.

FIG. 11 shows a schematic chart for explaining another example of aneffect of the method for processing the substrate of the embodiments.More specifically, FIG. 11 is a chart showing a wet etching rate of theobtained films.

As shown in FIG. 11, the silicon nitride film obtained by the workingexample 1 had an etching rate lower than the silicon nitride filmobtained by the comparative examples 1 and 2. That is to say, it isnoted that the silicon nitride film obtained by the method forprocessing the substrate of the working example 1 is preferablyavailable for intended purpose of a mask and the like in an etchingprocess. This is because the method for processing the substrate of theworking example 1 could modify the nitride film more efficiently bypassing the substrate through the area having the small ion energy andthe low radical concentration (second process area P2) and then passingthe substrate through the area having the great ion energy and the highradical concentration (third process area P3) in the plasma treatment.

An evaluation was performed to determine whether the loading effect canbe prevented by the method for processing the substrate of the workingexample 1.

FIGS. 12A and 12B show schematic charts for explaining another exampleof an effect of the method for processing the substrate of the workingexample 1. More specifically, FIGS. 12A and 12B are charts plotting adecreasing rate of a film thickness from a target film thickness in an Xaxis direction (FIG. 12A) and in a Y axis direction (FIG. 12B),respectively. In the working example 1, the Y axis direction is adirection linearly connecting the center of the wafer W to therotational center of the turntable 2 (this direction is made positive),and the center of the Y axis coincides with the center of the wafer W.Moreover, the X axis direction is an axial direction perpendicular tothe Y axis direction and passing a principal surface of the wafer W. Thecenter of the X axis coincides with the center of the wafer W, and apositive direction of the X axis is a direction heading for thedownstream from the upstream in the rotational direction of theturntable 2.

As shown in FIGS. 12A and 12B, the decreasing rates of the workingexample 1 are smaller than those of the comparative example 2 in both ofthe X axis direction and the Y axis direction. In other words, it wasnoted that the method for processing the substrate of the workingexample 1 can prevent the generation of the loading effect.

Working Example 2

A description is given below of a working example in which arelationship between a distance from the plasma generation unit to thewafer W and an amount of nitriding the wafer W in itself.

A film deposition process was performed on a wafer W under the followingconditions by the method for processing the substrate as described withreference to FIG. 9 by using the substrate processing apparatus of theembodiments as described with reference to FIGS. 1 through 8.

As the film deposition conditions, the first distance in step S120 andthe second distance in step S130 are set at the same value. Morespecifically, the values are set at 30 mm, 37.5 mm, 60 mm and 90 mm, andthe amount of nitriding the wafer W after the film deposition processwas measured at each of the setting distances.

FIG. 13 is a schematic chart for explaining another example of an effectof the method for processing the substrate of the working example 2.

As shown in FIG. 13, an amount of nitriding the wafer W increases withthe decreasing distance between the plasma generation unit and the waferW. This means that the ion energy of plasma and the density of radicalsincrease with the decreasing distance between the plasma generation unitand the wafer W. In particular, because the precursor has a greatinfluence on the wafer W and the wafer W is likely to be nitrided initself in the initial stage of the film deposition process, passing thewafer W through the area having the great ion energy and the highradical concentration (the third process area P3) after passing thewafer W through the area having the small ion energy and the low radicalconcentration (the second process area P2) is preferable like the methodfor processing the substrate of the working example 2.

As discussed above, it was noted that the generation of the loadingeffect can be prevented and a thin film having a desired film qualitycan be deposited by passing a substrate through an area having a smallion energy and a low radical concentration (second process area P2) andthen by passing the substrate through an area having a great ion energyand a high radical concentration (third process area P3) from theworking examples 1 and 2.

Working Example 3

In a method for processing a substrate of a working example 3, acomparative experiment of an amount of film deposition, a film qualityand the like was performed between the case of rotating the turntable 2in a clockwise fashion illustrated by the arrow of FIG. 2 and the caseof rotating the turntable 2 in a counterclockwise fashion opposite tothe arrow of FIG. 2 by using the substrate processing apparatusdescribed with reference to FIGS. 1 through 8.

FIG. 14 is a diagram illustrating a process flow of an example of themethod for processing the substrate of the working example 3, and theprocess flow is performed when the turntable 2 is rotated in theclockwise fashion the same as the arrow of FIG. 2. Here, in the workingexample 3, a description is given below by citing an example of usingDCS that is a silicon-containing gas as the first process gas, a mixedgas composed of ammonia gas, hydrogen gas and argon gas as the firstplasma processing gas, and ammonia gas as the second plasma processinggas. Here, a flow rate of each gas contained in the first plasmaprocessing gas was as follows: ammonia gas is 0.3 slm; hydrogen gas is0.6 slm; and argon gas is 1.9 slm. The first plasma processing gas was ahydrogen-rich gas. Also, the second plasma processing gas was composedof hundred-percent ammonia, and the flow rate thereof was 4 slm. Byrotating the turntable 2 in a counterclockwise fashion, the wafer Wsequentially passed the first process area P1, the separation area D,the first plasma generation unit 81 a (which may be hereinafter called a“first plasma treatment area” or “first plasma process area”), thesecond plasma generation unit 81 b (which may be hereinafter called“second plasma treatment area” or “second plasma process area”), and theseparation area D, and a process flow illustrated in FIG. 14 wasrepeated.

FIGS. 15A through 15C are diagrams illustrating a chemical reactionmodel that occurred on a surface of a wafer W when performing theprocess flow in FIG. 14. FIG. 15A is a diagram illustrating a state inwhich the first plasma treatment is performed on the wafer W by thefirst plasma generation unit 81 a. In the first plasma treatment, byperforming the plasma treatment on the surface of the wafer W on whichDCS had adsorbed by the first plasma composed of (NH₃+H₂+Ar), NHadsorbed on the surface of the wafer W, and then Si adsorbed on NH,thereby having terminated with hydrogen. Here, Cl and H of DCS reactedwith each other and was released as HCl.

FIG. 15B is a diagram illustrating a state in which the second plasmatreatment was performed on the wafer W by the second plasma generationunit 81 b. When DOS was supplied, as illustrated in FIG. 15B, becausethe adsorption site terminated with NH₂, Si could readily adsorb to NHby causing the terminated H and Cl of DCS to react with each other so asto escape as HCl.

In this manner, by nitriding and modifying a Si-containing film withfirst plasma containing hydrogen gas and then by nitriding so as to forman adsorption site with second plasma containing ammonia gas and nohydrogen gas, DCS could readily adsorb to the adsorption site when DCSwas supplied. This causes the loading effect to be preferable, therebyefficiently depositing a Si-containing film.

FIG. 16 is a diagram illustrating an example of a process flow of amethod for processing a substrate according to a comparative example.The process flow in FIG. 16 is performed when rotating the turntable 2in a counterclockwise fashion opposite to the arrow in FIG. 2. ComparingFIG. 16 with FIG. 14, a processing order of the first plasma treatmentand the second plasma treatment is made opposite, and the first plasmatreatment by the mixed gas of hydrogen gas, ammonia gas and argon gaswas performed after performing the second plasma treatment by onlyammonia gas.

FIGS. 17A through 17C are diagrams illustrating a chemical reactionmodel that occurred on a surface of a wafer W when performing theprocess flow of the method for processing the substrate illustrated inFIG. 16. FIG. 17A is a diagram illustrating a state in which the firstplasma treatment (first time) was performed on the wafer W by the secondplasma generation unit 81 b. In the first plasma treatment, byperforming a plasma treatment with the first plasma composed of NH₃ on astate in which DCS had adsorbed on a surface of the wafer W, theterminated H and NH of the plasma react with each other, therebyterminating with NH₂.

FIG. 17B is a diagram illustrating a state in which the second (secondtime) plasma treatment was performed on the wafer W by the first plasmageneration unit 81 a. By performing a plasma treatment on the wafer W onwhich DCS had absorbed with the second plasma composed of (NH₃+H₂+Ar),the terminated NH₂ and Cl reacted with each other and got away as HCl,thereby having terminated H.

FIG. 17C is a diagram illustrating a state in which DCS of the firstprocess gas was supplied to the wafer W in the first process area P1.When DCS was supplied, as illustrated in FIG. 17B, because theadsorption site terminated with H, DCS was difficult to adsorb thereto.

Thus, even though the Si containing film was nitrided by the firstplasma containing ammonia gas and no hydrogen gas and then theSi-containing film was nitrided and modified by the second plasmacontaining hydrogen gas, the Si-containing film terminated with Hwithout forming an adsorption site and became difficult for DCS toadsorb thereto when DCS was supplied. This does not make the loadingeffect preferable, and does not cause the Si-containing film to bedeposited efficiently.

TABLE 1 shows results of films deposited all over a whole flat surfaceof a wafer W by the method for processing the substrate of the workingexample 3 of the present invention and by the method for processing thesubstrate of the comparative example. With respect to the processconditions, a substrate temperature was 400 degrees C., and a pressureinside the vacuum chamber 1 was 0.75 Torr. A flow rate of DCS was 1000sccm (further 500 sccm of N₂ was supplied), and a flow rate of ammoniagas in the first plasma treatment area 81 a was 300 slm. A flow rate ofhydrogen gas was 600 sccm, and a flow rate of argon gas was 1900 sccm. Aflow rate of ammonia gas in the second plasma treatment area 81 b was4000 slm, and a flow rate of N₂ gas in the separation areas D was 3000sccm.

TABLE 1 ITEM CCW CW Win AVG (nm) 24.2599 22.4666 Max (nm) 24.618422.9386 Min (nm) 23.7627 21.6213 Range (nm) 0.856 1.317 DEPO rate(nm/min) 0.651 0.601 CYC rate (nm/cycle) 0.065 0.060 Win Unif (± %) 1.762.93 Thickness 24.26 22.47

As shown in TABLE 1, a deposition rate per one cycle in the method forprocessing the substrate of the working example 3 was 0.065 nm/cycle,and a deposition rate per one cycle in the method for processing thesubstrate in the method for processing the substrate of the comparativeexample was 0.060 nm/cycle. The deposition rate per one cycle of themethod for processing the substrate of the working example 3 was about8% higher than that of the comparative example. Moreover, the uniformitywithin a surface of the method for processing the substrate of theworking example 3 was 1.76%, and the uniformity within a surface of themethod for processing the substrate of the comparative example 3 was2.93%. The uniformity within a surface of the method for processing thesubstrate of the working example 3 was preferable to that of thecomparative example.

FIG. 18 is a chart showing a comparative result of the uniformity withinthe surface in an X line between the method for processing the substrateof the working example 3 and the method for processing the substrate ofthe comparative example when a pattern was formed in a wafer W and thewafer W had a surface area ten times as large as that of a wafer Whaving a flat surface. As shown in FIG. 18, a curve Ax showing theuniformity within the surface in the method for processing the substrateof the working example 3 is widely lower than a curve Bx showing theuniformity within the surface in the method for processing the substrateof the comparative example, and indicates a preferable uniformity withinthe surface.

FIG. 19 is a chart showing a comparative result of the uniformity withinthe surface in a Y line between the method for processing the substrateof the working example 3 and the method for processing the substrate ofthe comparative example when a pattern was formed in a wafer W and thewafer W had a surface area ten times as large as that of a wafer Whaving a flat surface. As shown in FIG. 19, a curve Ay showing theuniformity within the surface in the method for processing the substrateof the working example 3 is widely lower than a curve By showing theuniformity within the surface in the method for processing the substrateof the comparative example, and indicates a preferable uniformity withinthe surface.

In this manner, the method for processing the substrate of the workingexample 3 could obtain better results in both of the film depositionrate and the uniformity within the surface than that of the method forprocessing the substrate of the comparative example.

Here, the method for processing the substrate of the working example 3can be implemented not only by the substrate processing apparatusillustrated in FIGS. 1 through 8, but also by a substrate processingapparatus whose first and second plasma generation units 81 a and 81 bhave the same height as each other. Because the method for processingthe substrate of the working example 3 focuses on the supply order ofthe plasma processing gases, the method for processing the substrate ofthe working example 3 can be applied to the substrate processingapparatus without respect to the height of the plasma generation units81 a and 81 b.

According to the embodiments of the present invention, there is provideda method for processing a substrate and a substrate processing apparatusthat can prevent the generation of the loading effect and deposit a thinfilm having a desired film quality.

All examples recited herein are intended for pedagogical purposes to aidthe reader in understanding the invention and the concepts contributedby the inventor to furthering the art, and are to be construed as beingwithout limitation to such specifically recited examples and conditions,nor does the organization of such examples in the specification relateto a showing of the superiority or inferiority of the invention.Although the embodiments of the present invention have been described indetail, it should be understood that various changes, substitutions, andalterations could be made hereto without departing from the spirit andscope of the invention.

What is claimed is:
 1. A method for processing a substrate, comprisingsteps of: supplying a silicon-containing gas to a surface of a substrateprovided in a chamber so as to cause the silicon-containing gas toadsorb on the surface of the substrate; converting thesilicon-containing gas adsorbed on the surface of the substrate to an Hterminated silicon by performing a first plasma treatment on the surfaceof the substrate having the silicon-containing gas adsorbing on thesurface of the substrate using a first plasma generated from a firstplasma processing gas containing hydrogen gas and ammonia gas; anddepositing a silicon nitride film and modifying the silicon nitride filmwhile converting the H terminated silicon to an NH₂ terminated siliconby performing a second plasma treatment on the surface of the substratesubject to the first plasma treatment using a second plasma generatedfrom a second plasma processing gas containing ammonia gas and nohydrogen gas.
 2. The method as claimed in claim 1, wherein the step ofsupplying the silicon-containing gas to the surface of the substrate,the step of performing the first plasma treatment on the surface of thesubstrate and the step of performing the second plasma treatment on thesurface of the substrate are repeated in a cycle.
 3. The method asclaimed in claim 2, further comprising a step of: supplying a purge gasto the surface of the substrate immediately before and after the step ofsupplying the silicon-containing gas to the surface of the substrate. 4.The method as claimed in claim 2, wherein the chamber includes therein aturntable capable of receiving the substrate thereon, and a firstprocess area capable of supplying the process gas to the surface of thesubstrate, a first plasma treatment area capable of performing the firstplasma treatment on the surface of the substrate and a second plasmatreatment area capable of performing the second plasma treatment on thesurface of the substrate that are arranged along a rotational directionof the turntable, and wherein the step of supplying thesilicon-containing gas to the surface of the substrate, the step ofperforming the first plasma treatment on the surface of the substrateand the step of performing the second plasma treatment on the surface ofthe substrate are repeated in a cycle by passing the substrate throughthe first process area, the first plasma treatment area and the secondplasma treatment area in this order by rotating the turntable.
 5. Themethod as claimed in claim 4, wherein purge gas supply areas forsupplying a purge gas to the surface of the substrate are provided onboth sides of the first process area, and further comprising a step of:supplying the purge gas to the surface of the substrate before and afterthe step of supplying the silicon-containing gas to the surface of thesubstrate.
 6. The method as claimed in claim 1, wherein the first plasmaprocessing gas is a mixed gas containing hydrogen gas, ammonia gas andargon gas.
 7. The method as claimed in claim 1, wherein the secondplasma processing gas consists of ammonia gas.
 8. The method as claimedin claim 1, wherein the process gas contains at least one ofdiisopropylamino-silane, tris(dimethylamino)silane,bis(tertiary-butyl-amino)silane, dichlorosilane, hexachlorodisilane,titanium tetrachloride, titanium methylpentanedionatobis(tetramethylheptanedionato), trimethylaluminium,tetrakis(ethylmethylamino)zirconium, tetrakis (ethylmethylamino)hafnium,and strontium bis(tetramethylheptanedionato).